Windows XP Home and Professional SP3 includes the MSI-based
.NET Framework 1.1 + SP1 in the Additional Components folder
on the installation CD. It is not an OS component on this OS.
Well, I would start by reviewing the runonce explanation Here. After that, copy your .net binaries to the root of the cd before creating the ISO. After that, add the runonce commands found Here to the runonce section under the unattended tab (ensuring that they are tailored for your setup, ie the paths are right in the commands). That should work for you. Good Luck.
Best Answer
No, .NET Framework 2.0 was not included with Windows XP SP3.
See here: